Indicator mechanism

ABSTRACT

I disclose an indicating mechanism comprising a support means on said support for defining an indicator path means and a drive member recess, said path means communicating with said recess, a drive member rotatably mounted within said recess, and an elongated flexible indicator joined to said drive member and at least partially wrapped thereabout, said indicator extending from said recess into and along said path means.

United States Patent 2,014,485 9/1935 Themar Inventor Harvey G. SkinnerLigonier, Pa.

May 2, 1969 Mar. 9, 1971 Westmoreland Plastics Inc.

Latrobe, Pa.

Appl. No. Filed Patented Assignee INDICATOR MECHANISM 16 Claims, 10Drawing Figs.

U.S.Cl 116/135, 116/115,116/133 Int. Cl G091 5/00 FieldofSearch 116/124,124.1, 133, 135, 115, 115.5; 73/305;

74/(Inquired); 219/(lnquired); 338/(Inquired) References Cited UNITEDSTATES PATENTS 2,232,057 2/1941 Fa1lereta1.... 116/135 2,348,362 5/1944Rudolf 73/305X 2,529,832 11/1950 Brietzke 116/135 2,529,833 11/1950Brietzke 116/135 2,538,188 1/1951 Brietzke 116/135 3,040,700 6/1962Smith, Jr. 1 16/135 3,139,854 7/1964 Hedges et a1. 116/135 PrimaryExaminerLouis .I. Capozi AttorneyBue1l, Blenko & Ziesenheim 57 v 47 a 1N 15 IV 1 .-58 ./52 "234% 72 F q 6 56 NA 39 16 a 0 1- -52 X 45 1? I T?14 PATENTEDMAR BIS?! 3568.631

SHEET 1 UF 2 PATENTED MAR 9 mm SHEET 2 0F 2 n a w an i W W MG a 4 H W.

rnnrcnron MECHANISM The present invention relates to an indicatormechanism and more particularly to a mechanism of this character fortranslating rotary motion of relatively small radius to an external,larger scale movement for indicating purposes.

in the construction and use of various types of electrical equipment, acontrol or console panel frequently is provided. These panels orconsoles frequently contain a number of rotary controls secured to theinside of the panel and having an operator knob protruding therethrough.The gas or electrical controls may involve variable resistances,conductances, capacitances, rotary switches and the like which areelectrically connected to circuitry forming part of the electricalequipment, or gas flow.

With the increasing complexity of modern electrical, gas, and electronicequipment, a logical tendency toward miniaturization follows. The smallsizes of the control knobs render their scale indicia difficult to read,as the scale indicia conventionally are inscribed on the knob ordisposed closely thereabout. Moreover, inaccuracy frequentlyresults inboth the placement and reading of scale indicia where the size thereofis limited in this manner. An indicating needle or pointer affixed tothe control knob, when used, is usually spaced from the scale indiciaand thus engenders further inaccuracies from parallax. t

Considerable improvement'in readability, both from the standpoints ofaccuracy and facility, can be had if these scales are made larger andtherefore more easily read and calibrated. It is particularly desirableto-have the movement ofthe rotary control translated into a movement ofan indicator tape or the like disposed for movement along the path whichis removed at least a short distance from the rotary control knob. Suchpath may be linear, curvalinear, or arcuate depending upon the spacelimitations imposed by the control panel or console construction.

Most importantly, it has been established that an operator can moreeasily follow, with greater accuracy, the indicating end of a movabletape or other flexible indicator rather than the motion of a pointer orother indicating member affixed to a control knob and movable over ascale printed on or otherwise afiixed to the panel. Additionally, theconventional scale may substantially surround the control knob, wherethe control has nearly a 360 rotation. The operatorss fingers, then,frequently obstruct a portion of the scale during adjustment of thecontrol.

in the past there have been a number of attempts to solve this problem,for example the U. S. Pat. Nos. to Brietzke 2,529,832 and 2,529,833;Smith, Jr. 3,040,700; and Hedges et al. 3,139,854. Each of thesereferences contemplates unwrapping a flexible indicating tape or memberfrom a rotary component of the control device. The indicating tape isthen forced into an external, usually liner linear, indicating path.None of these references, however, are capable of use with a rotarycontrol device capable of an increasing function in the clockwisedirection or interchangeably with such device capable of increasingfunction in the opposite direction without substantial changes instructure. Obviously, if a rotary control having an increasing functionin the opposite direction were substituted for those shown in theforegoing references, the scale indicia along the external path ofindicating tape would have to be reversed. This would render reading ofthe scale indicia confusing, particularly where both clockwise andcounterclockwise indicator systems or devices were used on a givenpanel. in that case some of the scale indicia may be inverted relativeto other indicia to make reading more difficult. The

prior art, moreover, does not disclose an indicator system I overcomethese disadvantages of the prior art by providing a rotary controldevice from which an indicator tape or strip is unwrapped for movementinto external path means for cooperation with scale indicia along suchpath means. In one arrangement of my invention, the path means aredisposed for receiving the indicator tape from either a clockwiseincreasing control device or one which evidences an increasing functionin the opposite direction. indicia associated with the path means do nothave to be inverted irrespective of the rotational direction of therotary control in'supplying increasing increments of the controlledfunction.

in other arrangements of my invention the path means are arranged in anarcuate fashion. A portion of the path means may be displaced from thecontrol knob for easy reading by placing the path means and theassociated scale indicia entirely above, below, or to one side of thecontrol knob such that the scale is not obstructed by the user'sfingers. In furtherance of this purpose the indicia portion of thearcuatepath means can be provided with substantially the same center ofrotation as that of the rotary controluIn any event the necessity ofsubstantially surrounding the control knob with small and difficult toread scale indicia is obviated. In accordance with a specificmodification of my invention I arrange the external path means of theindicator tape to connect the indicia portion of the path means with apoint on the wrap area of the rotary control by meansof a smooth curve,such as a spiral section or Archimedes curve.

Finally, I arrange my novel indicator mechanism as a unitary structuresuch that a control knob forming part thereof is retained on a controlshaft, upon securing the mechanism to the panel on which the control ismounted. I also provide stop means, forming part of the indicatormechanism, for the control knob and hence for the control securedthereto.

I accomplish these desirable results by providing an indicatingmechanism comprising a support means on said support for defining anindicator path means and a drive member recess, said path meanscommunicating with said recess, a drive member rotatably mounted withinsaid recess, and an elongated flexible indicator joined to said drivemember and at least partially wrapped thereabout, said indicatorextending from said recess into and along said path means.

I also desirably provide a similar indicating mechanism wherein saidpath means include a pair of indicating paths adjoined with said recessat locations remote from one another to provide indications ofincreasing function for a preselected one of clockwise andcounterclockwise movements of said drive member.

I also desirably provide a similar indicating mechanism wherein saidpath means include an arcuate path spacedly and partially surroundingdrive member.

I also desirably provide a similar indicating mechanism wherein saiddrive member is of discoidal configuration, said indicator is at leastpartially wrapped about the peripheral edge thereof, said indicatorbeing positioned on said edge by the adjacent surfaces of said supportand said defining means.

I also desirably provide a similar indicating mechanism wherein saidsupport includes a transparent cover and a base member, said base memberhaving said defining means thereon, and a detachable overlay indiciaplate is sandwiched between said cover and said base member, saidoverlay plate having visual access means generally aligned with at leasta portion of said path means.

I also desirably provide a similar indicating mechanism wherein portionsof said defining means and of said drive member are disposedrespectively to bearingly engage portions of said indicator to providestops for respectively delimiting movements of said drive member and ofa rotary control coupled thereto.

l also desirably provide a similar indicating mechanism includingacontrol knob for a rotary control mounted on said support and secured tosaid drive member for rotation therewith, means on said knob and saidcontrol for keying said knob to said control for rotation therewith,said control being mounted on an external support member, and means formounting said support on said support member so that said knob ismaintained in keyed engagement with said control.

During the foregoing discussion, various objects, features andadvantages of the invention have been set forth. These and otherobjects, features and advantages of the invention together withstructural details thereof will be elaborated upon during theforthcoming description of certain presently preferred embodiments ofthe invention and presently preferred methods of practicing the same.

In the accompanying drawings I have shown certain presently preferredembodiments of the invention and have illustrated certain presentlypreferred methods of practicing the same, wherein:

FIG. 1 is a front elevational view of one form of indicator mechanismarranged in accordance with my invention;

FIG. 2 is a side elevational view of the mechanism as shown in FIG. 1;

FIG. 3 is a rear elevational view of the mechanism as shown in FIG. 1and taken along reference line III-III thereof;

FIG. 4 is a cross-sectional view of the apparatus as shown in FIG. 3 andtaken along reference line IV-IV thereof:

FIG. 4A is a partial cross-sectional view of the apparatus as shown inFIG. 3 and taken along reference line IVA-IVA thereof;

FIG. 5 is a partial front elevational view of the mechanism of FIG. 1and showing another position of the indicator;

FIG. 6 is a front elevational view of another form of my indicatormechanism with parts removed for clarity;

FIG. 6A is a similar front elevational view of the mechanism of FIG. 6showing another position of the indicator and associated components;

FIG. 7 is another front elevational view of the indicator mechanism ofFIG. 5 showing a cover plate and indicia overlay attached; and,

FIG. 8 is a sectional view of the mechanism generally as shown in FIG. 7and taken along reference line VIII-VIII thereof.

Referring now more particularly to FIGS. 1-5 of the drawings theexemplary indicator mechanism 10 shown therein comprises a support 11including a front panel plate 12, a base member 14, a drive wheel 16 anda flexible indicating strip 18. The base member 14 in this example isprovided with a pair of securance studs 20 (FIG. 2) whereby theindicator mechanism 10 can be secured to a control or console panel 22,for example by a pair of Tinnermans clips 24.

The indicator mechanism 10 is located on the panel 22 for engagementwith a rotary control device 26, which can be secured to the oppositeside of the panel 22 in any conventional fashion. The control 26 may beprovided with one or more electric leads 28 for connection to othercircuit components (not shown) for controlling various electrical,fluid, or gas apparatus. In this example, the control 26 is providedwith a keyed operating rod or shaft 30 which extends through suitableapertures 31 and 32 in the base member 14 and the front panel 12respectively. The shaft 39 likewise extends through a keying recess 34(FIG. 2) in extension 35 of control knob 36. The knob extension 35 inturn is inserted through drive wheel 16, which is enclosed within recessmember 37 in this example formed integrally on the base member 14. Thedrive wheel 16 is keyed at 38 to the knob extension 35 which in turn iskeyed at flats 39 to the control shaft 30 for rotation therewith. Thedrive wheel is further enclosed between the base member 14 arid thecover plate 12. When the indicator mechanism 10 is mounted on the panel22, on which the control 26 is mounted, the knob 36 is retained on thecontrol shaft 30 by the studs 20 and clips 24, or other suitablesecurance means, which secure the mechanism 10 to the panel 22.

Although the drive wheel 16 is of discoidal configuration, in thisexample, the indicator strip 18 is maintained on the peripheral edge ofthe drive wheel by the close fitting relation of the recess-definingportions 37, 37a and the adjacent surfaces of the base member 14 and thecover plate 12 as evident from FIGS. 1 and 2.

Adjoining the recess member 37 of the base member 14 are a number ofwall sections 40, 42 which with the recess members 37, 37a can be formedintegrally with the base member 14, for example by molding from asuitable plastic. The aforementioned mounting studs 20 can be similarlyand integrally molded. The outer wall sections 42, in this example, arelinear extensions of the recess member 37, while the inner wall sections40 are connected at their lower ends (as viewed in FIG. 1) to thearcuate recess member section 37a. A pair of indicator paths 44, 46 arethus defined respectively by the inner and outer wall sections 40, 42and adjacent surfaces of the base member 12 and panel 14. The paths 44,46 adjoin the drive wheel recess 48 at the communicating areas 50, 52respectively. The drive wheel recess 48, which generally surrounds theapertures 31, 32 is substantially enclosed and defined by the recessmembers 37, 37a and by the adjacent surfaces of the base member andfront plates 12, 14.

The cover plate 12 can be provided with one or more indicating slots forexample the slot 45 through which the free end 47 of the indicatingstrip 18 is visible. An additional indicating slot as indicated by chainoutline 49 can also be provided if desired in the cover plate 12 in theevent that the indicator strip 13 is redirected into path 46 rather thanpath 44 as shown in FIG. 1. The alternate indicating slot 49 may beprovided as a knockout, or a separate cover plate (not shown) having anindicator slot 49 in place of the slot 45 can be provided. Thealternative indicating paths 44, 45 provide for reversal of theindicating movement of the strip 18 as set forth in greater detailbelow.

Alternatively, the cover plate 14 an can be fabricated from atransparent material, and separate overlay plate 53 (FIG. 2) having theslot 45 or 49 and the indicia 63 (described below) can be positionedbetween the cover plate 14 and the base member 12. To reverse theindicator movements, i.e., when shifting the indicator 18 from path 44to path 46, the overlay plate simply is reversed for a correspondingshift in the indicator slot. The overlay plate conveniently can beprovided with indicia 68 on both obverse and reverse sides for thispurpose.

The drive wheel 16 desirably is provided with a pair of displacedconnecting means to which the drive end 54 of the strip 18 alternativelycan be secured. In this example the aforementioned connecting meansinclude a pair of indents or slots 56, 58, and in this example the strip18 is secured to the left or clockwise slot 56 so that a proper lengthof the indicator or strip 18 can be extended into path 44. Infurtherance of this purpose the strip 18 is provided with a keying endportion 60 which is fitted into a complementarily shaped portion of theselected drive wheel slot 56 or 53. Depending upon the resiliency of thematerial forming a strip 18, the strip can be provided if desired with aliving hinge or restricted section 62 to facilitate bending of the endportion 54 of the strip 18 around the adjacent corner 64 or 66 of thedrive wheel 16.

At the low or start position of the control 26 and its operating shaft30 the indicator strip is wrapped substantially around the entireperipheral edge of the drive wheel 16 (FIG. 1). The indicating end 47 ofthe strip 18 is protruded through the communicating area 50 between thedrive wheel recess 48 and the clockwise indicating path 44. Accordinglythe indicator end 47 of the strip 18 encounters increasing scale indicia68 during clockwise movement of control knob 38 (solid arrow 70), as thefunction controlled by the control 26 is varied in the increasingdirection. Atthe initial strip position or minimum indication (FIG. 3),the engagement of the strip bend 67 with the adjacent portion of thestrip 18 urges this portion against the adjacent path defining wallsection 42 to act as a stop for the drive wheel 16 and the control knob36 and control shaft 30 keyed thereto. The lower or minimum limit of thefunction controlled by the rotary control 26 is thereby established, avery useful arrangement fo those instances when the rotary control 26 islacking in integral stop or motion-delimiting means or when delimitationdiffering from that afforded by a given control is desired. Similarly,as shown in FIG. 4A, control movement can be delimited in the maximumdirection by contact of the strip indicating end 47 with a stop member69 formed by the top inside surface of the support 11. Although theindicator is relatively flexible, it is sufficiently rigid to resistbuckling particularly in the communicating area 50 or 52, where theindicator is only partially supported, at the adjaeent wall section 12.Throughout the remainder of the movement path of the strip 10, thelatter is relatively closely confined between the adjacent wall sections40, 42 or between the recess wall 317 and the drive wheel 16.

in the event that a counterclockwise control (not shown) as substitutedfor the rotary control 26, the indicator strip 18 is removed from itskeyed engagement with drive wheel slot 56 and engaged in drive wheelslot 50. At such time the strip is wrapped in the opposite directionabout the peripheral edge of the drive wheel 16, and its indicating endis protruded through communicating area 52 into the alternative orcounterclockwise indicating path 46 as denoted by partial chain outline72 of the indicator 10. The indicator 72, then, will properly denoteincreasing scale indicia for counterclockwise movement of a rotarycontrol (not shown) associated with the indicating mechanism 10 (dashedarrow 74). As noted previously the indicia 60 and a suitable slot orwindow 45 or 49 can be formed on the opaque overlay plate 53 (FIG. 2).

Referring now to FIGS. 6-8 another arrangement 80 of my indicatormechanism is shown for the purpose of translating rotary movement ofacontrol device into movement along an external arcuate path forindicating purposes. In this arrangement the indicating mechanism 80 hasa support 81 including a generally circular base member 02 having inthis example a central aperture 0% and path defining wall sections 06,08. The base member 02 is also provided with securance studs the purposeand function of which have been described previously. The centralaperture 84 of the base member 02 affords passage of a control shaft andcontrol knob extension for a suitable rotary control mechanism 26 (FIG.53).

The inner wall section 86 additionally defines a generally cireuiarrecess 90 in which is mounted drive wheel 92. The drive wheel 92 isprovided with a generally central recess 94 including key 96 for keyingengagement with a control knob extension 00 (FlGS. 6 and 6A) of controlknob 99.

The drive member 92 is provided with strip slot 100 having a keyingconfiguration and into which a similarly shaped end portion 102 of aflexible indicator strip 10 is inserted for securance to the drivemember 92.

The wall sections 86, 00 define a generally arcuate indicator path 106therebetween which is further enclosed by the ad jacent surfaces of thebase member 82 and a cover plate 108 (F168. 7 and 8). The indicator path106 communicates at the area denoted generally by reference character110 with the drive member recess 90. Accordingly indicator strip 104extends from its connection with and partial wrapping about the drivemember 92 through the communicating area 110 and thence along theindicator path 106.

in the arrangement shown in FIG. 6A the drive member 92 has been rotated(arrow 112) in the clockwise direction to a point corresponding to itsmaximum setting. As a result the indicating end 47 of the indicatorstrip 10 1 is at the high end of the scale indicia denoted by referencecharacter 114 (FIG. 7).

At this point motion of the indicator mechanism 80 can be delimited byengagement of the indicator end 47' with stop 115 at the maximum end ofthe indicator path 106 after the manner of FIG. 5. In many cases it ispreferable to delimit movement of the indicator mechanism 00 in themaximum direction short of the stop 115 by disposing the wall end 12%and the driving wheel projection 117 to bearingly engage the adjacentportion of the strip 10d to prevent further movement of the drive wheel92 and associated components. The strip 104 is not sufficientlyresilient as to be forced into an S-bend by such engagement and to allowcontinued movement of the drive wheel 92. Naturally, both of these stopmeans can be employed in concert to ensure stoppage of further drivewheel rotation.

The scale indicia 11d and if desired an indicator slot corresponding towindow 116 can be formed directly upon the front cover plate 108.Desirably, however, the front cover plate is made from a transparentplastic material, and a separate relatively thin, opaque indicia plate110 is secured between the cover plate and the base member 82. Thisfacilitates provision of differing scale indicia for variousapplications. If desired, the indicia plate can be likewise fabricatedfrom a transparent plastic material and provided with an opaque coatingsave for the window area 116. The indicia plate 110 and the cover plate100 are provided with central apertures 120, 122 for passage of anoperating shaft or control knob extension 90.

Referring again to FIGS. 6 and 6A, it will be seen that the flexibleindicator strip 104 proceeds along a smooth curve or arcuate path fromits connection with the drive member 92 and along the generally spiralindicating path 106. Desirably the initial portion of the path 106 isconformed to an Archimedes or similar type curve for this purpose. Infurtherance of this purpose the adjacent surfaces of the wall sections86, 80 are given a similar configuration. The drive member 92 desirablyis provided with a similar Archimedes curve section 107 to facilitatepaying 011 the strip 104 along a relatively smooth curved path andparticularly to avoid bending the strip 104 over the adjacent end ofwall section 06, except as noted above.

Likewise, a portion 105 of the recess side of the inner wall 86 and theadjacent edge 107 of the drive wheel 92 are similarly andcomplementarily configured to follow the aforesaid Archimedes or spiralcurve. The remaining portions 109, 111 of the wall 86 and drive wheel92, in this example, are of circular contour. When the drive wheel ismoved to its minimum position (FIG? 6) the strip 104 becomes boundbetween the surfaces 109, 111 to prevent further movement of the drivewheel 92 and to delimit correspondingly the minimum setting of controlknob 90 and the rotary control attached thereto. At this point theindicating end 47' of the strip 104 is at the minimum end of slot 116(FIGS. 6A and 7).

With the arrangement of FIGS. 6& it is possible to group the pertinentscale indicia, such as the indicia 114, generally to one side of theoperating knob (such as knob 38 of FIG. 2) and to dispense with thecustomary pointer or other indicator affixed to the knob. With thisarrangement, as better shown in FIG. 6, the scale 114 can be more easilyand accurately read. In the embodiments shown, the indicia portion ofthe path 106 is generally circular about a point substantiallyconcentric with that of the operating shaft 90, while the preliminaryportion 124 of the indicator path 106 conforms to an Archimedes curve orspiral portion as noted above. it will be understood, of course, thatany smoothly curving configuration can be employed between the indiciaportion of the path 106 and the transfer or communicating area 110.Obviously, too, the indicia portion can conform to a path having a shapeother than circular.

The indicating direction of the indicator mechanism d0 can be relativelyreversed simply by reversing the drive member 02 on the shaft orextension 98, by similarly reversing overlay 118 if used, and byproviding a base member 82 having relatively reversed wall sections 86,0d. The latter can be accomplished simply by turning over the die plateor the like (not shown) used in molding the base member 82.

Desirably the overlay plate 110 is provided with a symmetricallydisposed locating notch for cooperation with locating tab 132 on thepath defining plate 82. Desirably, the indicia plate 110 is placedbetween the cover plate 100 and the path defining member 02 where theindicia plate is further positioned and confined by rim 13 i formingpart of the cover plate 100. In this example, the cover plate rim 13 1is fitted closely about the outer surface 130 of the outer path definingwall 8%, which can be made circular for this purpose.

From the foregoing it will be apparent that novel and efficient forms ofIndicator Mechanisms have been described herein. While 1' have shown anddescribed certain presently preferred embodiments of the invention andhave illustrated presently preferred methods of practicing the same, itis to be distinctly understood that the invention is not limited theretobut may be otherwise variously embodied and practiced within the spiritand scope of my disclosure.

I claim:

1. An indicating mechanism comprising a support, means on said supportfor defining an indicator hollow path means and a drive member recess,said path means communicating with said recess, a drive member rotatablymounted within said recess, an elongated flexible indicator joined tosaid drive member and extending from said recess into and along saidpath means, said drive member being of discoidal configuration, saidindicator being at least partially wrapped about the peripheral edgethereof, said indicator being positioned on said edge solely by theadjacent surfaces of said support and said defining means and theadjacent end portion of said path means, and said support including acover having visual access means therein aligned with at least a portionof said path means.

2. The combination according to claim 1 wherein said means are providedfor detachably joining said indicator to saiddrive member, said drivemember joining means extending generally in the direction of said pathmeans so that said indicator can be detachably joined to said drivemember without substantial bending.

3. The combination according to claim 1 wherein said support includes atransparent cover and a base member, said base member having saiddefining means thereon, and a detachable overlay indicia plate issandwiched between said cover and said base member, said overlay platehaving visual access means generally aligned with at least a portion ofsaid path means.

4. The combination according to claim 1 wherein portions of saiddefining means and of said drive member are disposed respectively tobearingly engage portions of said indicator to provide stops forrespectively delimiting movement of said drive member and of a rotarycontrol coupled thereto.

5. The combination according to claim 1 including a control knob for arotary control mounted on said support and secured to said drive memberfor rotation therewith, means on said knob and said control for keyingsaid knob to said control for rotation therewith, said control beingmounted on an external support member, and means for mounting saidsupport on said support member so that said knob is maintained in keyedengagement with said control. I

6. The combination according to claim 1 wherein said path means includean arcuate path spacedly and at least partially surrounding drivemember.

7. The combination according to claim 6 wherein at least the initialportion of said path is a spiral section and a portion of said drivemember is similarly shaped.

8. The combination according to claim 7 wherein said spiral sectionconforms to an Archimedes curve.

9. An indicating mechanism comprising a support, means on said supportfor defining an indicator path means and a drive member recess, saidpath means communicating with said recess, a drive member rotatablymounted within said recess, and an elongated flexible indicator joinedto said drive member and at least partially wrapped thereabout, saidindicator extending from said recess into and along said path means,said path means including a pair of indicating paths adjoined with saidrecess at locations remote from one another to provide indications ofincreasing function for a preselected one of clockwise andcounterclockwise movements of said drive member.

10. The combination according to claim 9 wherein scale indicia aresecured to said support and disposed generally along said path means.

11. The combination according to claim 9 wherein said support isprovided with visual access means corresponding to at leasta ortion ofsaid path means.

12. e combination according to claim 9 wherein said drive member isprovided with dual connection means for said indicator correspondingrespectively to the relative locations of said paths to facilitatechanging of said indicator from one path to another.

13. The combination according to claim 9 wherein means are provided fordetachably joining said indicator to said drive member, said joiningmeans extending generally in the direction of said path means so thatsaid indicator can be detachably joined to said drive member withoutsubstantial bending.

14. The combination according to claim 9 wherein said support includes atransparent cover and a base member, said base member having saiddefining means thereon, and a detachable overlay indicia plate issandwiched between said cover plate and said base member, said overlayplate having visual access means generally aligned with at least aportion of said path means.

15. The combination according to claim 9 wherein portions of saiddefining means and of said drive member are disposed respectively toengage bearingly portions of said indicator to provide stops forrespectively delimiting movements of said drive member and of a rotarycontrol coupled thereto.

16. The combination according to claim 9 including a control knob, arotary control mechanism, said knob being secured to said drive memberfor rotation therewith, means on said knob and said control for keyingsaid knob to said control for rotation therewith, said control beingmounted on an external support member, and means for mounting saidsupport on said support member so that said knob is maintained in keyedengagement with said control.

1. An indicating mechanism comprising a support, means on said supportfor defining an indicator hollow path means and a drive member recess,said path means communicating with said recess, a drive member rotatablymounted within said recess, an elongated flexible indicator joined tosaid drive member and extending from said recess into and along saidpath means, said drive member being of discoidal configuration, saidindicator being at least partially wrapped about the peripheral edgethereof, said indicator being positioned on said edge solely by theadjacent surfaces of said support and said defining means and theadjacent end portion of said path means, and said support including acover having visual access means therein aligned with at least a portionof said path means.
 2. The combination according to claim 1 wherein saidmeanS are provided for detachably joining said indicator to said drivemember, said drive member joining means extending generally in thedirection of said path means so that said indicator can be detachablyjoined to said drive member without substantial bending.
 3. Thecombination according to claim 1 wherein said support includes atransparent cover and a base member, said base member having saiddefining means thereon, and a detachable overlay indicia plate issandwiched between said cover and said base member, said overlay platehaving visual access means generally aligned with at least a portion ofsaid path means.
 4. The combination according to claim 1 whereinportions of said defining means and of said drive member are disposedrespectively to bearingly engage portions of said indicator to providestops for respectively delimiting movement of said drive member and of arotary control coupled thereto.
 5. The combination according to claim 1including a control knob for a rotary control mounted on said supportand secured to said drive member for rotation therewith, means on saidknob and said control for keying said knob to said control for rotationtherewith, said control being mounted on an external support member, andmeans for mounting said support on said support member so that said knobis maintained in keyed engagement with said control.
 6. The combinationaccording to claim 1 wherein said path means include an arcuate pathspacedly and at least partially surrounding drive member.
 7. Thecombination according to claim 6 wherein at least the initial portion ofsaid path is a spiral section and a portion of said drive member issimilarly shaped.
 8. The combination according to claim 7 wherein saidspiral section conforms to an Archimedes curve.
 9. An indicatingmechanism comprising a support, means on said support for defining anindicator path means and a drive member recess, said path meanscommunicating with said recess, a drive member rotatably mounted withinsaid recess, and an elongated flexible indicator joined to said drivemember and at least partially wrapped thereabout, said indicatorextending from said recess into and along said path means, said pathmeans including a pair of indicating paths adjoined with said recess atlocations remote from one another to provide indications of increasingfunction for a preselected one of clockwise and counterclockwisemovements of said drive member.
 10. The combination according to claim 9wherein scale indicia are secured to said support and disposed generallyalong said path means.
 11. The combination according to claim 9 whereinsaid support is provided with visual access means corresponding to atleast a portion of said path means.
 12. The combination according toclaim 9 wherein said drive member is provided with dual connection meansfor said indicator corresponding respectively to the relative locationsof said paths to facilitate changing of said indicator from one path toanother.
 13. The combination according to claim 9 wherein means areprovided for detachably joining said indicator to said drive member,said joining means extending generally in the direction of said pathmeans so that said indicator can be detachably joined to said drivemember without substantial bending.
 14. The combination according toclaim 9 wherein said support includes a transparent cover and a basemember, said base member having said defining means thereon, and adetachable overlay indicia plate is sandwiched between said cover plateand said base member, said overlay plate having visual access meansgenerally aligned with at least a portion of said path means.
 15. Thecombination according to claim 9 wherein portions of said defining meansand of said drive member are disposed respectively to engage bearinglyportions of said indicator to provide stops for respectively delimitingmovements of said drive member and of a rotary control coupled thereto.16. The combination according to claim 9 including a control knob, arotary control mechanism, said knob being secured to said drive memberfor rotation therewith, means on said knob and said control for keyingsaid knob to said control for rotation therewith, said control beingmounted on an external support member, and means for mounting saidsupport on said support member so that said knob is maintained in keyedengagement with said control.